2005-10-23 20:52:11

by David Singleton

[permalink] [raw]

2005-10-24 03:57:54

by Sven-Thorsten Dietrich

[permalink] [raw]
Subject: Re: Robust Futexes status

On Sun, 2005-10-23 at 13:52 -0700, david singleton wrote:
> Inaky Perez-Gonzalez has a wonderful suite of performance, stress and
> functionality tests for the fusyn pthreads mutex package.

> The graphs are just to show relative performance for the different
> flavor kernels. The
> kernel's perform quite closely regardless of the 'flavor' of kernel.
> The kernels have quite a few
> debugging options turned so I can look for any problems so performance
> is not optimal.
>

The Mutex ownership change seems to climb with waiting threads.

Its hard to tell with the log-n X-axis scale, but does this possibly
correlate to the deadlock-detect option?

If Deadlock-detect is enabled we should be seeing a graph proportional
to n-squared on a linear X axis.

If deadlock detect is disabled, the wait time should plateau for very
large N.

Sven


> It appears the robust futex functionality is healthy in all flavors of
> kernel.
>
>
>
> David
>
>
>
>
--
***********************************
Sven-Thorsten Dietrich
Real-Time Software Architect
MontaVista Software, Inc.
1237 East Arques Ave.
Sunnyvale, CA 94085

Phone: 408.992.4515
Fax: 408.328.9204

http://www.mvista.com
Platform To Innovate
***********************************

2005-10-24 17:02:15

by David Singleton

[permalink] [raw]
Subject: Re: Robust Futexes status


On Oct 23, 2005, at 8:48 PM, Sven-Thorsten Dietrich wrote:

> On Sun, 2005-10-23 at 13:52 -0700, david singleton wrote:
>> Inaky Perez-Gonzalez has a wonderful suite of performance, stress
>> and
>> functionality tests for the fusyn pthreads mutex package.
>
>> The graphs are just to show relative performance for the different
>> flavor kernels. The
>> kernel's perform quite closely regardless of the 'flavor' of kernel.
>> The kernels have quite a few
>> debugging options turned so I can look for any problems so performance
>> is not optimal.
>>
>
> The Mutex ownership change seems to climb with waiting threads.
>
> Its hard to tell with the log-n X-axis scale, but does this possibly
> correlate to the deadlock-detect option?

It could be. I have been running all the tests mainly as stress and
functionality tests.
>
> If Deadlock-detect is enabled we should be seeing a graph proportional
> to n-squared on a linear X axis.
>
> If deadlock detect is disabled, the wait time should plateau for very
> large N.

The original run script ran up to 7500 waiting threads. I ran a version
that only went up to 400 threads.

When I get full performance data I'll post it.

David
>
> Sven
>
>
>> It appears the robust futex functionality is healthy in all flavors
>> of
>> kernel.
>>
>>
>>
>> David
>>
>>
>>
>>
> --
> ***********************************
> Sven-Thorsten Dietrich
> Real-Time Software Architect
> MontaVista Software, Inc.
> 1237 East Arques Ave.
> Sunnyvale, CA 94085
>
> Phone: 408.992.4515
> Fax: 408.328.9204
>
> http://www.mvista.com
> Platform To Innovate
> ***********************************
>